Structure and photoluminescence properties of zinc oxide/ytterbium oxide nanocomposites

Nanocomposites based on zinc oxide and ytterbium oxide nanocrystals with Yb atomic content varied from 0.5 up to 6 % were synthesized from alcohol solutions followed by thermal annealing in air. The prepared samples were characterized by means of the X-ray diffraction, transmission electron microscopy and photoluminescence spectroscopy. A sharp photoluminescence line of Yb³⁺ ions was detected at 983 nm and it was stronger for the samples thermally annealed at 750 °C. The intensity of Yb³⁺ photoluminescence was found to be slightly depended on Yb concentration and to exhibit a square root dependence on excitation intensity. The experimental results are explained by assuming energy transfer from the photoexcited zinc oxide nanocrystals to ytterbium oxide nanoparticles on their surface. The obtained results indicate possible applications of Yb-doped zinc oxide nanostructures in optoelectronics devices and as infrared biomarkers.